Cooking device having a microwave generator

The invention relates to a cooking device comprising a microwave generator, a cooking chamber wall delimiting a cooking chamber, in which a through opening is provided, and a cooking chamber sieve associated with the through opening.

In particular, the cooking device is a cooking device for professional applications, such as those used in canteens, restaurants and large-scale catering. With such a cooking device, food can be cooked in a cooking chamber atmosphere, which may be hot air, steam or a cooking chamber atmosphere with adjustable humidity. Depending on the cooking program, it is possible to additionally or exclusively heat the food using microwave radiation.

The through opening can lead to a drainage system, by means of which it is possible to drain off impurities produced during the cooking process or cleaning liquid from the cooking chamber. The through opening is usually arranged in the bottom of the cooking chamber. The cooking chamber sieve is assigned to the through opening to prevent larger dirt particles from entering the drainage system through the through opening and possibly clogging it.

To enable the cooking chamber sieve to be cleaned quickly if necessary, it is detachably arranged at the through opening. In view of the thermal and chemical stresses to which the cooking chamber sieve is exposed, stainless steel is usually used as the material for the cooking chamber sieve.

Usually, the cooking chamber wall is also made of stainless steel. When microwave radiation is introduced into the cooking chamber, an electrical potential can build up between the cooking chamber sieve and the cooking chamber wall. Depending on the geometric conditions, the potential difference can discharge in the form of electric arcs between the cooking chamber sieve and the cooking chamber wall. Users of the cooking device may be irritated by such electric arcs. In addition, the electric arcs may damage the material of the cooking chamber sieve and/or the cooking chamber wall.

The object of the invention is to prevent electric arcs between the cooking chamber sieve and the cooking chamber wall, while still allowing the cooking chamber sieve to be quickly and easily removed from the cooking chamber drain, for example, for cleaning.

To achieve this object, a cooking device is provided according to the invention, comprising a microwave generator, a cooking chamber wall delimiting a cooking chamber, in which a through opening is provided, and a cooking chamber sieve associated with the through opening, wherein at least one intermediate element is provided between the cooking chamber wall and the cooking chamber sieve, which serves to mount the cooking chamber sieve to the cooking chamber wall, and wherein the at least one intermediate element is configured such that the generation of electric arcs between the cooking chamber wall and the cooking chamber sieve is prevented. Due to the dual function (i.e. prevention of the generation of electric arcs between the cooking chamber sieve and the cooking chamber wall on the one hand and mounting of the cooking chamber sieve on the other hand), both requirements can be met reliably with little effort.

Advantageously, the at least one intermediate element produces a non-destructively detachable connection between the cooking chamber sieve and the cooking chamber wall. This makes it possible to remove the cooking chamber sieve if necessary to be able to clean it easily.

The at least one intermediate element may be arranged on the side of the cooking chamber sieve facing the cooking chamber wall above a cooking chamber sieve collar and may fill the area towards the cooking chamber wall. In this way, the intermediate element has good mechanical contact with both the cooking chamber sieve and the through opening.

Alternatively, at least two intermediate elements may be arranged on the side of the cooking chamber sieve facing the cooking chamber wall above the cooking chamber sieve collar, and an air gap may remain between the cooking chamber sieve and the cooking chamber wall. This has the advantage that less material is required for the manufacture of the intermediate elements and that individual intermediate elements are replaced if they are damaged. Again, the cooking chamber sieve does not contact the cooking chamber wall, as the assembly of the cooking chamber sieve takes place exclusively via the intermediate elements.

The at least one intermediate element may be provided, on the side facing the cooking chamber sieve, with at least one attachment means which engages in a recess provided in the cooking chamber sieve and locks the intermediate element to the cooking chamber sieve. The mechanical engagement ensures that the cooking chamber sieve is reliably locked in position and cannot come loose unintentionally.

The at least one intermediate element may have at least one latching means on the side facing the cooking chamber wall, which cooperates with a latching edge in the through opening of the cooking chamber wall, so that the cooking chamber sieve is positively locked. By means of such a latching means, the desired holding force for the cooking chamber sieve can be provided and it can be determined from which tensile force it can be detached from the through opening.

Alternatively, the at least one intermediate element may be configured as a spring element on the side facing the cooking chamber wall, so that the cooking chamber sieve is non-positively locked in the region of the through opening of the cooking chamber wall. The spring element can also be used to set how much force is required to lock or release the cooking chamber sieve in the through opening.

The at least one intermediate element may be configured to be electrically conductive and establish an electrical contact between the cooking chamber sieve and the cooking chamber wall. The electrical contact ensures a potential equalization, through which the current can flow through the intermediate element from one component to the other. Thus, it is ensured that no electric arcs can occur, as the electrical resistance between the two components via the intermediate element is significantly lower than that via an air gap between the two components.

Advantageously, the at least one intermediate element may have a meander spring and/or disk spring made of metal. These springs are particularly robust and durable as well as cost-effective and simple to manufacture. In addition, the spring elements can compensate for manufacturing tolerances and variations in component dimensions due to thermal influences.

Alternatively, the at least one intermediate element may be an electrical insulator and prevent an electrical potential equalization between the cooking chamber sieve and the cooking chamber wall. If the intermediate element is arranged on the side of the cooking chamber sieve facing the cooking chamber wall above the cooking chamber sieve collar and fills the area towards the cooking chamber wall, it completely insulates the transition. If several intermediate elements are arranged on the side of the cooking chamber sieve facing the cooking chamber wall above the sieve collar, the intermediate elements themselves and the air filling the air gap act as insulation. In both cases, potential equalization can thus be prevented. The size of the air gap is specified via the distance, which is determined by the intermediate element.

Alternatively, the at least one intermediate element may consist of a dielectric material. The dielectric material prevents a current flow between the cooking chamber wall and the cooking chamber sieve and prevents or reduces the generation of electric fields. This applies in particular to electric fields at the component edges, where field strength increases may occur due to the geometry.

In addition, the cooking chamber sieve and the through opening of the cooking chamber wall may be provided with radii to reduce the previously mentioned electric field strength increase at the component edges. This also helps to prevent undesired electric arcs.

In, a cooking deviceis shown schematically.

The cooking devicehas a cooking chamber, which is formed by a cooking chamber walland can be closed by means of a cooking chamber door. To improve clarity, a representation of the door has been omitted in.

The cooking chamber wallhas a cooking chamber bottom, in which a through openingis provided.

A cooking chamber sieveis associated with the through opening, which is detachably locked in the through openingof the cooking chamber bottomand can be detached from the through openingin a non-destructive manner, in particular to clean the cooking chamber sieve.

The cooking chamber sieveperforms the function of separating solids from liquids. The term “sieve” is not to be understood restrictively at this point and is used as a generic term for sieves, grids or also filters. Thus, this term refers to all components that perform the function of separation due to their mesh or pore size.

shows the cooking chamber sieveand an intermediate elementaccording to a first variant. The cooking chamber sievehas a pan- or cup-shaped sieve sectionand a collar. The collarextends in a wreath shape around the upper end of the sidewall of the sieve section. The sieve sectionincludes openingsin both the bottom portion and the sidewall, which perform the functions of separation and prevent larger dirt particles from entering the drainage system.

The collarhelps to collect larger dirt particles which accumulate on the cooking chamber bottomoutside the cup- or pan-shaped sieve section, so that the majority of all dirt particles around the cooking chamber sieveaccumulate on the outside of the sidewall of the sieve sectionand the openingsin the bottom area are not blocked by the coarse dirt particles. The liquids produced during the cooking process flow into the drainage system as soon as the level reaches the openingslocated in the sidewall or the upper edge of the collar, or as long as the spaces between the dirt particles allow drainage along the bottom of the cooking chamber. In addition, the collarmay serve to support the intermediate elementin the axial direction. Furthermore, the collarprovides a good grip due to its shape, which facilitates assembly and disassembly of the cooking chamber sieve.

The sidewall of the sieve sectionis provided with a plurality of recesses.

The recessesprovide an attachment means for mounting the intermediate element.

The intermediate elementserves to provide the previously described non-destructively detachable connection between the cooking chamber sieveand the through openingof the cooking chamber bottom.

The intermediate elementis arranged on the exterior side of the sidewall of the sieve sectionbelow the collarand extends completely along the sidewall so that there is a planar contact between the intermediate elementand the sidewall.

For locking the intermediate elementto the cooking chamber sieve, the latter includes an attachment meanson the side facing the sieve section, which is held in the recesses. According to a first variant, the attachment meansis formed in a hook-shape and engages in the recesses, thus creating a positive connection. However, it is also conceivable to configure the cooking chamber sievewithout the recessesand to lock the intermediate elementon the cooking chamber sieveby means of a frictional connection.

To be able to produce a non-destructively detachable connection between the cooking chamber sieveand the cooking chamber wall, the intermediate elementis configured as a spring elementon the side facing the cooking chamber wallin accordance with a first variant. In this way, the intermediate elementcan produce a non-positive connection by radial tensioning between the cooking chamber walland the cooking chamber sieve.

The pressing-in and holding force required to lock or release the cooking chamber sievein the through openingis defined based on the design of the spring element.

Meander springs and/or disk springs are particularly suitable as spring element, but other types of springs are also conceivable. When meander springs are used, the openings between the meander spring and the through opening, if possible, should be smaller than the openingsin the cooking chamber sieve. Alternatively, the spring can additionally also be covered with a sleeve, which closes the openings.

show a further variant for the use of an intermediate elementconfigured with a spring element.

In this variant, the cooking chamber sievehas a circumferential abutmentwhich acts as an axial stop along the central axis M. The abutmentcan be configured in one piece with the cooking chamber sieve, but it is also conceivable that it is locked in the recesses.

The abutmentlies in a planar manner on the cooking chamber wall. The spring elementis arranged on the opposite side of the cooking chamber walland is compressed in the axial direction between the cooking chamber walland a clamping plateby means of a clamping element. A spring or a screw, for example, can be used as the clamping element. In this variant, the use of a wave spring is suitable as the spring element.

To prevent the generation of electric arcs between the cooking chamber sieveand the cooking chamber wall, electrically conductive materials are used for the previously described variants of the intermediate elementwhich are configured with a spring element, to ensure a potential equalization between the cooking chamber sieveand the cooking chamber wall. Thus, these variants are based on the principle of electrical contacting. Both the intermediate elementand the spring elementare therefore preferably made of metal with good electrical conductivity.

The spring elementensures constant electrical contact between the cooking chamber sieveand the cooking chamber wall, which is compensated even in the event of a deviation in the dimensional accuracy of the components resulting from manufacturing tolerances or thermally induced component deformations. For example, a spring steel can be used for the spring element.

Furthermore, the intermediate elementand the spring elementeasily withstand the temperatures prevailing in cooking chambers.

Optionally, it would be conceivable to manufacture the spring elementfrom any material and then sheathe it with an electrical insulator to prevent the generation of electric arcs by an electrical insulation.

show a second variant of the cooking chamber sieve. In contrast to the first variant, a plurality of intermediate elementsare arranged on the exterior side of the sidewall of the sieve sectionin the second variant. In the areas of the sidewall of the sieve sectionon which no intermediate elementis arranged, there is an air gap between the sidewall and the through opening. The dimensions of this air gap are in a size ratio similar to the openingsmanufactured in the cooking chamber sieve, so that the sieving effect is still maintained. Alternatively, the plurality of intermediate elementsmay be arranged such that the end faces of the ends are in an abutting relationship and no air gap is formed.

The intermediate elementis thus arranged between the cooking chamber sieveand the cooking chamber wall. Therefore, there is no direct contact between the cooking chamber sieveand the through opening. The thickness d of the intermediate elementdefines the minimum distance between the cooking chamber sieveand the cooking chamber wall.

In addition, the intermediate elementin this variant has a latching meanswhich cooperates with the latching edgeon the through openingand locks the cooking chamber sievein place with a positive fit. The intermediate elementincludes an intermediate element stopon the side of the cooking chamber wallopposite the latching means. The intermediate element stoplimits the movement along the central axis M during assembly of the cooking chamber sieve. It can thus be ensured that the cooking chamber sieveis locked in a defined position in the assembled state. On the basis of the latching meansof the intermediate element, it is possible to determine the force with which the cooking chamber sievemust be pressed in for assembly, and the force required to release the cooking chamber sieveagain.

shows an alternative to the second variant. In contrast to the second variant, the intermediate elementdoes not have any latching means. Instead, the intermediate elementhas a slightly conical shape which allows the cooking chamber sieveto be pressed into the through openingand produces a frictional connection. In this alternative, the intermediate elementmay be configured as a ring extending around the cooking chamber sievealong the sidewall, leaving no air gap between the sidewall and the through opening.

show further variants of the attachment meansof the intermediate element. In all these variants, it is conceivable that the intermediate elementis arranged in the through openingand the cooking chamber sieveis held in the attachment means, or that the intermediate elementis locked in the through openingalong with the cooking chamber sieve. All subsequent intermediate elements, which are described as being half-ring-shaped, can only be used in combination with a further intermediate element. In this case, the ends thereof are configured such that they engage in each other with a positive fit and the end faces thereof lie on top of each other.

shows an intermediate elementwhich is configured to have the shape of a half ring and has a plurality of attachment meansarranged on webs projecting in the axial direction, which are similar to a semicircular cylinder and extend in sections along the circumference on the inside towards the side facing the cooking chamber sieve, and on the cylinder outer surface of which a latching geometry is additionally arranged. Furthermore, the half-ring-shaped intermediate elementhas a groovealong the circumference on the side facing the cooking chamber wall, which surrounds the cooking chamber wallin the area of the through openingin the assembled state.

shows a half-ring-shaped intermediate element, which is provided with a plurality of frustoconical attachment meanson the side facing the cooking chamber sieve. On the outer side, the intermediate elementalso has the groove.

shows a half-ring-shaped intermediate element, which has attachment meansarranged on webs projecting in the axial direction, the ends of the webs having a latching geometry. Analogous to the variants described above, this intermediate elementalso has a groove.

shows a half-ring-shaped intermediate element, the attachment meansof which is configured in the form of a latching geometry. On the side facing the cooking chamber wall, this variant also has a groove.

shows a half-ring-shaped intermediate element, the attachment meansof which is in the form of a plurality of semicircular cylinders on the side facing the cooking chamber sieve. This variant also has a grooveon the outer side.